Alien Vs. Predator Requiem.
Me and my father see a film or two a month, so off we drive to the good cinema (20miles, but its nicer than ours) and he forgets his wallet (something my father rarely does). I got my wallet, so I pay.
We sit though the most predictable, cliché story while I internally go "He's going to die, he probably will, they'll die before I ... yep, head splattered".
We both come out of the cinema saying its the worst thing we've ever seen, we now use it as the yard stick to measure how bad other films are.